The long non-coding RNA DANA2 positively regulates drought tolerance by recruiting ERF84 to promote JMJ29-mediated histone demethylation

Identification of cell-type specificity, trans- and cis-acting functions of plant lincRNAs from single-cell transcriptomes

Long noncoding RNAs, including intergenic lncRNAs (lincRNAs), play a key role in various biological processes throughout the plant life cycle, and the advent of single-cell RNA sequencing (scRNA-seq) technology has opened up a valuable avenue for scrutinizing the intricate roles of lincRNAs in cellular processes. Here, we identified a new batch of lincRNAs using scRNA-seq data from diverse tissues of plants (rice, Arabidopsis, tomato, and maize). Based on well-annotated single-cell transcriptome atlases, plant lincRNAs were found to possess the same level of cell-type specificity as mRNAs and to be involved in the differentiation of certain cell types based on pseudo-time analysis. Many lincRNAs were predicted to play a hub role in the cell-type-specific co-expression networks of lincRNAs and mRNAs, suggesting their trans-acting abilities. Besides, plant lincRNAs were revealed to have potential cis-acting properties based on their genomic distances and expression correlations with the neighboring mRNAs. Furthermore, an online platform, PscLncRNA (http://ibi.zju.edu.cn/psclncrna/), was constructed for searching and visualizing all identified plant lincRNAs with annotated potential functions. Our work provides new insights into plant lincRNAs at single-cell resolution and an important resource for understanding and further investigation of plant lincRNAs.

Biological Insights and Recent Advances in Plant Long Non-Coding RNA

Long non-coding RNA (lncRNA) refers to an RNA molecule longer than 200 nucleotides (nt) that plays a significant role in regulating essential molecular and biological processes. It is commonly found in animals, plants, and viruses, and is characterized by features such as epigenetic markers, developmental stage-specific expression, and tissue-specific expression. Research has shown that lncRNA participates in anatomical processes like plant progression, while also playing a crucial role in plant disease resistance and adaptation mechanisms. In this review, we provide a concise overview of the formation mechanism, structural characteristics, and databases related to lncRNA in recent years. We primarily discuss the biological roles of lncRNA in plant progression as well as its involvement in response to biotic and abiotic stresses. Additionally, we examine the current challenges associated with lncRNA and explore its potential application in crop production and breeding. Studying plant lncRNAs is highly significant for multiple reasons: It reveals the regulatory mechanisms of plant growth and development, promotes agricultural production and food security, and drives research in plant genomics and epigenetics. Additionally, it facilitates ecological protection and biodiversity conservation.

Decoding the functionality of plant transcription factors

Transcription factors (TFs) intricately govern cellular processes and responses to external stimuli by modulating gene expression. TFs help plants to balance the trade-off between stress tolerance and growth, thus ensuring their long-term survival in challenging environments. Understanding the factors and mechanisms that define the functionality of plant TFs is of paramount importance for unravelling the intricate regulatory networks governing development, growth, and responses to environmental stimuli in plants. This review provides a comprehensive understanding of these factors and mechanisms defining the activity of TFs. Understanding the dynamic nature of TFs has practical implications for modern molecular breeding programmes, as it provides insights into how to manipulate gene expression to optimize desired traits in crops. Moreover, recent studies also report the functional duality of TFs, highlighting their ability to switch between activation and repression modes; this represents an important mechanism for attuning gene expression. Here we discuss what the possible reasons for the dual nature of TFs are and how this duality instructs the cell fate decision during development, and fine-tunes stress responses in plants, enabling them to adapt to various environmental challenges.

Long Noncoding RNAs in Response to Hyperosmolarity Stress, but Not Salt Stress, Were Mainly Enriched in the Rice Roots

Due to their immobility and possession of underground parts, plants have evolved various mechanisms to endure and adapt to abiotic stresses such as extreme temperatures, drought, and salinity. However, the contribution of long noncoding RNAs (lncRNAs) to different abiotic stresses and distinct rice seedling parts remains largely uncharacterized beyond the protein-coding gene (PCG) layer. Using transcriptomics and bioinformatics methods, we systematically identified lncRNAs and characterized their expression patterns in the roots and shoots of wild type (WT) and ososca1.1 (reduced hyperosmolality-induced [Ca2+]i increase in rice) seedlings under hyperosmolarity and salt stresses. Here, 2937 candidate lncRNAs were identified in rice seedlings, with intergenic lncRNAs representing the largest category. Although the detectable sequence conservation of lncRNAs was low, we observed that lncRNAs had more orthologs within the Oryza. By comparing WT and ososca1.1, the transcription level of OsOSCA1.1-related lncRNAs in roots was greatly enhanced in the face of hyperosmolality stress. Regarding regulation mode, the co-expression network revealed connections between trans-regulated lncRNAs and their target PCGs related to OsOSCA1.1 and its mediation of hyperosmolality stress sensing. Interestingly, compared to PCGs, the expression of lncRNAs in roots was more sensitive to hyperosmolarity stress than to salt stress. Furthermore, OsOSCA1.1-related hyperosmolarity stress-responsive lncRNAs were enriched in roots, and their potential cis-regulated genes were associated with transcriptional regulation and signaling transduction. Not to be ignored, we identified a motif-conserved and hyperosmolarity stress-activated lncRNA gene (OSlncRNA), speculating on its origin and evolutionary history in Oryza. In summary, we provide a global perspective and a lncRNA resource to understand hyperosmolality stress sensing in rice roots, which helps to decode the complex molecular networks involved in plant sensing and adaptation to stressful environments.

Protocol for detecting lncRNA-protein interaction in vivo using the yeast three-hybrid assay

Analyses of long non-coding RNA (lncRNA)-protein interactions provide key clues for understanding the molecular basis of lncRNA-modulated biological processes. Here, we detail a yeast three-hybrid assay to identify the lncRNA-interacting protein. We describe steps for lncRNA bait preparation, screening an RNA-binding proteins (RBPs) cDNA library, and validation of the lncRNA-RBP interaction. The assay can also be further applied to delineate the region of RBP that mediates the RNA-protein interaction. For complete details on the use and execution of this protocol, please refer to Zhang et al.1.

Plant non-coding RNAs: The new frontier for the regulation of plant development and adaptation to stress

Most plant transcriptomes constitute functional non-coding RNAs (ncRNAs) that lack the ability to encode proteins. In recent years, more research has demonstrated that ncRNAs play important regulatory roles in almost all plant biological processes by modulating gene expression. Thus, it is important to study the biogenesis and function of ncRNAs, particularly in plant growth and development and stress tolerance. In this review, we systematically explore the process of formation and regulatory mechanisms of ncRNAs, particularly those of microRNAs (miRNAs), small interfering RNAs (siRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Additionally, we provide a comprehensive overview of the recent advancements in ncRNAs research, including their regulation of plant growth and development (seed germination, root growth, leaf morphogenesis, floral development, and fruit and seed development) and responses to abiotic and biotic stress (drought, heat, cold, salinity, pathogens and insects). We also discuss research challenges and provide recommendations to advance the understanding of the roles of ncRNAs in agronomic applications.

Tobacco roots increasing diameter and secondary lateral density in response to drought stress

Exploring the responses of root morphology and its physiological mechanisms under drought stress is significant for further improving water and nutrient absorption in roots. Here, we simulated drought through hydroponics combined with PEG treatments in tobacco to characterize the changes in tobacco root architecture. Our results showed the total root length, first lateral root number, and first lateral root length were significantly reduced upon increasing drought severity, but the average root diameter and secondary lateral root density increased under certain drought conditions. The change of auxin content in roots under drought stress was correlated with the root diameter and second lateral root density responses. Exogenous addition of the auxin analog (NAA) and the auxin transport inhibitor (NPA), as well as DR5:GUS staining experiments further demonstrated that auxin participated in this physiological process. Meanwhile, brassinolide (BR) exhibited a similar trend. Exogenous addition of BR (EBR) and the BR synthesis inhibitor BRZ experiments demonstrated that BR may participate upstream of auxin under drought stress. PEG treatment significantly up-regulated NtBRI1 at 9-24 h, and promoted the up-regulation of NtBSK2 and NtBSK3 at 48 h and 24 h, respectively, these genes may contribute to the change in root morphology under drought stress. This study shows that auxin and BR are involved in the changes in root morphology in tobacco exposed to drought stress. The elucidation of the molecular mechanism at play thus represents a future target for breeding drought-tolerant tobacco varieties.

Metabolic pathways engineering for drought or/and heat tolerance in cereals

Drought (D) and heat (H) are the two major abiotic stresses hindering cereal crop growth and productivity, either singly or in combination (D/+H), by imposing various negative impacts on plant physiological and biochemical processes. Consequently, this decreases overall cereal crop production and impacts global food availability and human nutrition. To achieve global food and nutrition security vis-a-vis global climate change, deployment of new strategies for enhancing crop D/+H stress tolerance and higher nutritive value in cereals is imperative. This depends on first gaining a mechanistic understanding of the mechanisms underlying D/+H stress response. Meanwhile, functional genomics has revealed several stress-related genes that have been successfully used in target-gene approach to generate stress-tolerant cultivars and sustain crop productivity over the past decades. However, the fast-changing climate, coupled with the complexity and multigenic nature of D/+H tolerance suggest that single-gene/trait targeting may not suffice in improving such traits. Hence, in this review-cum-perspective, we advance that targeted multiple-gene or metabolic pathway manipulation could represent the most effective approach for improving D/+H stress tolerance. First, we highlight the impact of D/+H stress on cereal crops, and the elaborate plant physiological and molecular responses. We then discuss how key primary metabolism- and secondary metabolism-related metabolic pathways, including carbon metabolism, starch metabolism, phenylpropanoid biosynthesis, γ-aminobutyric acid (GABA) biosynthesis, and phytohormone biosynthesis and signaling can be modified using modern molecular biotechnology approaches such as CRISPR-Cas9 system and synthetic biology (Synbio) to enhance D/+H tolerance in cereal crops. Understandably, several bottlenecks hinder metabolic pathway modification, including those related to feedback regulation, gene functional annotation, complex crosstalk between pathways, and metabolomics data and spatiotemporal gene expressions analyses. Nonetheless, recent advances in molecular biotechnology, genome-editing, single-cell metabolomics, and data annotation and analysis approaches, when integrated, offer unprecedented opportunities for pathway engineering for enhancing crop D/+H stress tolerance and improved yield. Especially, Synbio-based strategies will accelerate the development of climate resilient and nutrient-dense cereals, critical for achieving global food security and combating malnutrition.